Rhodamin dye and process of making same.



r UNITED STATES PATENT OFFICE.

nEINRIcH AUGUST. BERNTHSEN, or MANNHEIM, GERMANY, ASSIGNOR TO BADISCHEANILIN & SODA FABRIK GERMANY, A CORPORATION.

, OF LUDWIGSHAFEN-ON-TI-lE-RHINE,

RHODAMIN D-YE AND PROCESS OF MAKING SAME.

Specification of Letters Patent. Apulloation filed November 8, 1904.Serial No 231,90BQ (Specimens) I latented May; 22, 1906.

To all whom it may concern.-

Be it known that I, HEINRICH AUGUST BERNTHSEN, doctor of philosbphy, asubject of the King of Prussia, German Em eror, residing at Mannheim, inthe Grand uchy of Baden, in the German Empire, have invented new anduseful Improvements in Rhodamin Coloring-Matter and Processes ofProducing the Same, of which the following is a specification. I

All attempts made u to the present time to produce va monoalky atedrhodamin inter mediate.productthat is, a monoalkyl-amhdo-hydroxy-benzoyl-benzoic acid-by con densln to ether equal molecularpro ortions 0 pht alic anhydrid and a monoal ylmeta amido-phenolhavefailed because the .free hydrogen atom of the amido group takes in thecondensation and a different prodis obtained from that desired. I havediscovered a method by which these intermediate products can be obtainednamely, by condensin together e ual molecular proportions of pht ahmidan a monoalkyl meta amido phenol in the presence of boric acid and thensaponifying by means of caustic alkali or otherwise the newmonoalkyl-amidohydroXy-benzoylbenzamid so obtained. With the help ofthese new intermediate products I am enabled to manufacture new rhodamincoloringanatters of which the most important are the monoalkyl=rhod- 1of the esters remains clear.

amins made by condensing the new intermediate product with a molecularproportion' of meta-amido-phenol, and these may either be used as suchor they may be converted into their esters by suitable esterii'yingmeans. For instance, they may be heated with alcohol and sulfuric acid.The new rhodamins yield more yellowish shades of red than'any of thedyes of this series hitherto known in commerce, and they thereforeconstitute a valuable new class of coloringmatters. They are soluble inwater, giving red fluorescent solutions. If the solutions of theunesterified rhodamins containingone part in one thousand parts of waterhe allowed to stand, a precipitate forms, while the solution Ontreatment with hydrochloric acid and a nitrite the unesterified rhodaminsolutions become colorless ,or nearly so, and on pouring into analkasame treatment the esters ployed in the production of the saidintermediate product.

The rhodamins produced according to my invention may be used as such orthey may be employed in the form of their esters ,and I wish to beunderstood as' claiming these new rhodamins both in the form in whichthey contain a free carboxyl'grou and in the form of theirhydrochloric-acid sa ts have the composition corresponding to theformula cim=ssncl Hood-dmo o OBH3-NH2 and also in the form in which thecarboxyl group has been esterified, in which case theirhydrochloric-acid salts have the composition corresponding to theformula CBHs NRHCl in both of which formulae R represents an alkyl roup.

0 course in everycase instead of the metaamido phenol or monoalkyl metaamidofor instance, as para-methyhmetzt-amido-phenol homologues of thesecom oundssuch, phenol (generally known as ortho-amidopara-cresol andpara-methylmonoalkylmeta-amido-phenol (generally known as or tho-a1kylamidmpara-cresol )-may be used without departin from the nature of my in7 that in these compounds; the para position to the amido group orsubvention, provide stituted amido group is only occupied by hydrogen',and this of course efi 'ects a correspondmg cling-matters.

- The following examples .will serve to furalteration in the compositionof the 001- thirty-seven (137) parts of monoethyl-m etaamido-phenol, andone hundred and thirty.

ther illustrate the nature of my invention, which,however, is notconfined to these ex amples. The parts are by weight.

Example 1 Production of monoethylamide -hydrom'y benzoyl benzoicacid-Stir well together. one hundred and forty-seven (147) parts ofphthalimid, one hundred and (130) arts of crystallized boric acid andthen heat t ewhole for about three (3) hours, while stirring, at atemperature of from one hun- 7 becomes acid when tested with Congopaper.

. grade, (20-30 C.)

. soda.

thousand (6,000) :stand for a consic erable time, filter off the Thesubstituted benzoic acid which separates out can be filtered ofl, washedwith water, pressed, and dried.

Example 2P1'oduct'ion of monoethylrhodam'in.lntroduce ninety-six (96).parts of monoethyl-amido-hydroxy-benzoyl benzoic-acid hydrochlorid intoone thousand (1,000) parts of sulfuric acid containing about ninety-six(96) per cent. of H SO at ordinary temperature and after solution iseffected add slowly forty-five (45) parts of acetyl-meta-amidopl1enoland then stir the mixture for about six (6) hours at a temperature offrom twenty to thirty degrees centi- Then pour the melt into tenthousand (10,000) parts of water, boil the whole for three (3) hours,and then precipitate the coloring-matter from this solution by means ofcommon salt.

.If it be desired to purify the coloring-matter, rub it' with a littlewater and two hun-- dred (200) parts of caustic-soda solution con''tainin about thirty-five (35) per cent. of NaO and then dilute themixture with six arts of water. Allow to rhodamin base, and reconvert itin the usual manner into its hydrochlorid. I

Example 3 Production of monoethg/L homo-rhodamin.Introduce at ordinarytemperature ninety-six (96) parts ofmonoethylamido-hydroxy-benzoyl-benzoic-acid hydro chlorid into onethousand (1,000) parts of sulfuric acid containing about ninety-six(96per cent. of H SO and after solution is effected add slowly forty (40)parts of para-methylmeta amido-phenol, (generally known asortho-amido-para-crcsol. Allow the melt to standv over night, pour intowater, and makegslightly alkaline by means of caustic After allowing tostand for a considerable time filter off the rhodamin base and Thenfilter convert this in the usual manner into its hydrochlorid.

Example 4'P1'oducticm of monoethyZ-rhodam'im, ester.Mix together twenty(20) parts of monoethyl-rhodamin hydrochlorid, one hundred and sixty(160) parts of alcohol, and thirty (30) parts of sulfuric acidcontaining about'ninety six (96) per cent. of H and boil the wholegently on the water-bath for i from eight to ten (810) hours. Thendistil off the excess of alcohol, pour the residue into water, add alittle hydrochloric acid, and salt oult the coloring-matter by means ofcommon sa t.

If it be desired to obtain the ester free from any unester'ifiedrhodamin, dissolve the residue obtained after distilling off the alcoholin twenty thousand (20,000) parts of hot water and add twenty (20) partsof Rochelle salt. Allow to stand over night and filter off theunesterified rhodamin base and to the filtrate add a little hydrochloricacid and precipitate the rhodamin ester by means of common salt.

Instead of esterifying by means of alcohol and sulfuric acid in themanner described in this example any other known method of esterifyingrhodamins may be employedfor instance, the methods described in thespecifications of Letters Patents Nos. 499,927 and 516,584. v

Now what I clairn is-- l. The process for the production of rhod- I amincoloring-matters which consists in condensing phthalimid with amonoalkyl-metaamide-phenol, saponi'lying the benzamid obtained andcondensing the resulting product withpara-methyl-meta-amido pheno 4. Theprocess for the production of rhodamin coloringmatters which consists incondensing hthalimid with a monoalkyl-metaamidop 'enol, saponifying thebenzamid obtained, condensing the resulting product withpara-methyl-meta-amido-phenol, and esterifying the resultingcondensationprod uct.

5. The process for the production of rhodamin coloring-matters whichconsists in condensing phthalimid with monoethyl-metaamide-phenol,saponifying the benzamid obtained, and condensing theresulting productwith pera-methyl-meta-amido phenol.

6'. The process for the production of rhodrhodamincolorin '10 amincoloring-matters which consists in.con-' densmg' hthalimicl with amonoethyl-metaamido-p enol, sa poni ing the benzamid obtained, condensmt e resulting product with para-methy -meta-amido-phenol and esterifyingthe resulting condensation product.

- 7. As new articles of manufacture the -m atters obtainable by condensing a monoa kyl-rhod'amin intermediate product with ameta-amido-phenol, whichgron sis substituted y an ethyl group, and

whic upontreatment with hydrochloric acid and a nitrite or nearly sowhich onpourin into an alkaline beta-naphthol solution pro uces anorange color, and which coloring-matter in the form sition correspondingto the formula CeH:(GHs)-'-NH:. 9. As new articles of manufacture the{SEAL-1 V orinimatter proyields a colorless solution,

of its hydrochloric-acid salt has the compomy hand in the rhodamincolofinfi-(matters-obtainable by con- 4o densing amonoa yl-rhodaminintermediate product with a meta-amido-phenol and esterifying thecondensation product which coloring-matters are. completely soluble. incold water and which produce ellower shades of red than the rhodamins'thcrto known in commerce hydrogen atom of the amide groups issubstituted by-an alkyl cup.

p a new article of manufacture the rhod amin coloring-matter obtainableb con- (lensing monoethyl meta amido hy roxybenzoyl-benzoic acidwithpara-methyl-metaamide-phenol and esterifying the condense tion product,which coloring-matter produces ellower shades of red than the rhodaminsitherto known in commerce, '8Dd il1 which. only one hydrogen atom of theamide groups is substituted by an ethyl upon treatment with hydrochloricacid amt a nitrite yields a red solution which on pouring into analkaline beta-naphthol solution pro-1' itate andwhich in the duces adark preci form of its hydroc loric-acid salt has-the compositioncorresponding to the formula cartoon-0.11. 4 Gfid fid fi In testimonywhereof I have hereunto set presence of two subscribing witnesses.

Witnesses:

A. JEUTLINGER, Jos. II. Smrrn.

summon AUGUST 3 3mm It is hereby certified that in Letters Patent No.821,452, granted'May 22, f upon the-application of Heinrich AugustBernthsen, of Mannheim,

improvementin Rhol'lamin Dyes and Processes of Making Same,". in theprin ted specification requiring correction, as follows: On 1, lines to93 should read phenol, homologue: 01am compoumis such, for instance, a:pora -meihyl-mddamide-phenol; anil that the said Letters Patent shouldbe read with .this correction therein that .theszunemuy conform to therecord of the ease in the Patent Ofliee.

Signed and sealed mi; l7 th day of July, A. 1)., 1906,

Germany, for an an error appears 12.. B. MOORE, Q ActingComm-issimwr'ojli'aterm.

and in :which only one group, and which rhodamincolorin '10 amincoloring-matters which consists in.con-' densmg' hthalimid with amonoethyl-metaamido-p enol, sa poni ing the benzamid obtained, condensmt e resulting product with para-methy -meta-amido-phenol and esterifyingthe resulting condensation product.

- 7. As new articles of manufacture the -m atters obtainable by condensing a monoa kyl-rhod'amin intermediate product with ameta-amido-phenol, whichgron sis substituted y an ethyl group, and

whic upontreatment with' hydrochloric acid and a nitrite or nearly sowhich onpourin into an alkaline beta-naphthol solution pro uces anorange color, and which coloring-matter in the form sition correspondingto the formula CeH:(GHs)-'-NH:. 9. As new articles of manufacture the{SEAL-1 V orinimatter proyields a colorless solution,

of its hydrochloric-acid salt has the compomy hand in the rhodamincolofinfi-(matters-obtainable by condensing amonoa yl-rhodaminintermediate product with a meta-amido-phenol and esterifying thecondensation product which coloring-matters are. completely soluble. incold water and which produce ellower shades of red than the rhodamins'thcrto known in commerce hydrogen atom of the amide groups issubstituted by-an alkyl cup.

a new article of manufacture the and in :which only one rhod amincoloring-matter obtainable b (2011- (lensing monoethyl meta amido hyroxybenzoyl-benzoic acidwith para-methyl-metaamide-phenol andesterifying the condense tion product, which coloring-matter producesellower shades of red than the rhodamins itherto known in commerce, '8Ddil1 which. only one hydrogen atom of the amide groups is substituted byan ethyl upon treatment with hydrochloric acid amt a nitrite yields ared solution which on pouring group, and which into an alkalinebeta-naphthol solution pro-1' duces a dark preci form of its hydrocloric-acid salt has-the composition corresponding to the formulacartoon-0.11. 4 GJMCHO G In testimony whereof I have hereunto setpresence of two subscribing witnesses.

Witnesses:

A. JEUTLINGER, Jos. II. SEU'rE.

summon AUGUST marquees It is hereby certified that in Letters Patent No.821,452, granted'May 22, f upon the-application of Heinrich AugustBernthsen, of Mannheim,

improvementin Rhol'lamin Dyes and Processes of Making Same,". in theprin ted specification requiring correction, as follows: On 1, lines to93 should read phenol, homologue: 01am compoumis such, for instance, a:pera -meihyl-mddamide-phenol; anil that the said Letters Patent shouldbe read with .this correction therein that .theszunemuy conform to therecord of the ease in the Patent Ofliee.

Signed and sealed mi; l7 th day of July, A. 1)., 1906,

Germany, for an an error appears 12.. B. MOORE, Q ActingComm-issimwr'ojli'aterm.

itate andwhich in the It is hereby certified that in Letters Patent No.821,452, granted May 22, 1906, upon the application of Heinrich AugustBernthsen, of Mannheim, Germany, for an improvement in Rhodamin Dyes andProcesses of Making Same," an error appears in the printed specificationrequiring correction, as follows: On page 1, lines 91 to 93 should readphenol, homologue: of these compounds-such, for instance, a:para-mdhyl-mdw mnido-phmwl; and that the said Letters Patent should beread with this correction therein that the same may conform to therecord of the case in the Patent Oflicu.

Signed and sealed this I7th day of July, A. D., 1906.

E. B. MOORE,

Acting Commissioner ofPatenh.

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